Cold Sore While Pregnant: What to Know

Cold Sore While Pregnant: What to Know

A cold sore while pregnant is one of the less-than-glamorous realities you might encounter. 😩

If you’ve ever had a cold sore, you’ll know how annoying (and sometimes painful) these small blisters are.
They usually form around the mouth, and once you’ve had the virus that causes them, they can reoccur at any point.

But what causes cold sore breakouts?

It’s usually stress, tiredness, and hormonal changes.

And yep, this is all common during pregnancy.

If you’re worried about cold sores during pregnancy, here’s everything you need to know — and the best way to treat them.

In this article: 📝

  • What is a cold sore?
  • Can pregnancy cause cold sores?
  • Why is it common to have cold sores in pregnancy?
  • What causes cold sores on lips during pregnancy?
  • Are cold sores during pregnancy dangerous?
  • When to worry about cold sores during pregnancy
  • How do you treat a cold sore when pregnant?

What is a cold sore?

A cold sore is a tingly, painful red spot near your lip.

In technical terms, it’s a localized flare-up of the Herpes Simplex Virus (specifically HSV 1).

Also known as fever blisters, cold sores are annoying, uncomfortable, and very contagious.

About two-thirds of people have had the virus (but some don’t even know they have it as it is dormant).

And once you’ve been infected, you carry it for the rest of your life.

The virus can then reactivate at any time, becoming contagious and causing those pesky cold sores all over again.

Fun times.

Cold sores are more likely to break out if you’re stressed, your immune system is weakened, or your normal hormone balance is disrupted.

Sound like anything you know?

Can pregnancy cause cold sores?

Cold sores are incredibly common during pregnancy.

They’re so common, in fact, that cold sores before a positive pregnancy test are often seen as an early sign of pregnancy.

But are cold sores an early pregnancy symptom?

Well, not exactly.

Not on their own.

It’s important to know pregnancy itself doesn’t cause cold sores.

So if you haven’t had cold sores before, pregnancy won’t cause them.

If you’ve had a previous outbreak, though, all the stress, tiredness, and hormonal changes of pregnancy can make cold sores more likely.

Cold sores come from something called the Herpes Simplex Virus (HSV).

Once you’ve had a cold sore once (also known as oral or genital herpes), this virus stays in your system forever.

Herpes in your system, forever?! 😳

Yes, it sounds scary, but it’s really nothing to worry about.

The virus is dormant unless you have an active cold sore or other herpes breakout.

Why is it common to have cold sores in pregnancy?

If you’re wondering, are cold sores common in pregnancy? — it’s a resounding yes.

Cold sores during pregnancy are so common that most pregnant women experience them at some time.

This could happen at any point during your pregnancy.

Even if you haven’t had a cold sore for a long time, it’s still normal for cold sores to reoccur when you’re expecting.

The good news is cold sores don’t affect your growing baby.

Cold sores are a localized infection, so they don’t cross the placenta and reach your baby.

There are risks, though, if you get HSV (the virus causing cold sores) for the first time during your third trimester.

If this is the first time your body is dealing with HSV, the viral levels in your body are going to be pretty high, and you won’t have built up antibodies that can help protect your baby from the virus.

So, talk to your doctor or midwife if you’ve had cold sores for the first time (especially during later pregnancy). They’ll help you and baby stay safe.

A lot of women who’ve had a cold sore before will get another one during pregnancy.

It’s most likely to pop up in the first trimester when your immune system lowers its defenses to stop your body from attacking the little peanut who’s taken up residence in your uterus.

In early pregnancy, your hormones are also at their wildest (just check out this chart of how your hCG levels change).

And while we all wish we could switch off stress during pregnancy, it’s often easier said than done.

So are cold sores common in pregnancy?

Sadly, yes.

When you add all the factors together, it’s a perfect storm. ⛈

What causes cold sores on lips during pregnancy?

We’ve already seen how stress, tiredness, and hormones play a role in cold sore outbreaks.

But these things don’t cause cold sores in the first place.

This is down to Herpes Simplex Virus — HSV.

If you’ve never had this virus, you only catch it through contact with someone who has open cold sores.

This can happen through things like:

  • Kissing and close physical contact
  • Sharing food, cutlery, and cooking utensils
  • Sharing lip gloss and chapstick
  • Sex (including oral sex) with someone with the virus

So if you’re pregnant, this is a good time to be extra cautious about swapping germs.

Are cold sores during pregnancy dangerous?

Most of the time, a cold sore is just annoying and isn’t dangerous for either you or your little one.

If you get advice from your doctor first, they’re usually treatable too.

How do you treat a cold sore while pregnant?

The most common treatment of cold sores is a cream containing acyclovir or docosanol, which are both topical antivirals (i.e., you put them on your skin, and they fight the virus that’s causing your symptoms).

Both of these ingredients are on the table during pregnancy (some studies have shown that acyclovir is a bit safer.

But, because the CDC recommends these treatments for mamas-to-be only if the benefits outweigh the risks, you should ask your doctor or pharmacist before using them.

When to worry about cold sores during pregnancy

It’s also important to know that there are a few scenarios where a cold sore is more concerning for mamas-to-be.

If this is you, it’s best to inform your doctor and get advice about the next steps.

If it’s the first time you’ve ever had a cold sore

A recurring cold sore is an infection that sticks to the lining of your lips.

But your first herpes infection can affect your whole body, causing symptoms like fever, swollen gums, swollen lymph nodes, and a rash.

In this case, there’s a greater chance that the virus might cross the placenta to your baby.

If you have a cold sore during your third trimester

If you have a cold sore later in pregnancy, your doctor is more likely to offer you antivirals to clear up the infection before your baby is born.

This is because the same virus that causes cold sores in adults can make newborns very unwell if they catch it during birth or during their first few weeks earthside.

If you have an active (i.e., fresh, open, weeping) cold sore when your baby is born, you’ll have to take some steps to try to avoid passing the virus on.

As always, you should follow the advice of your healthcare team.

They will likely tell you to:

  • Wash your hands after you touch your face
  • Wash your hands before you pick your baby up
  • Cover the cold sore (for example, by wearing a clean face mask while feeding or burping your little one)
  • Avoid kissing your baby until after the cold sore has healed

And mamas, you should also ask anyone with a cold sore who visits your baby to take these same steps or wait a few days before they come over.

Not everyone knows about the risks of cold sores for little ones, so don’t be afraid to stand your ground on this one.

And FYI, the symptoms of a potentially dangerous herpes infection in newborns include:

  • Lethargy
  • Refusing feeds
  • Fever
  • Skin rash, including around the eyes and in the mouth

How do you treat a cold sore when pregnant?

Treating a cold sore in pregnancy can be tricky, as many medications aren’t evaluated for safety in pregnancy.

There are two main options, though: creams and tablets.

The first thing to do is chat with your healthcare provider.

They’ll give you the most up-to-date medical advice.

Your doctor might recommend things like acyclovir cream, available from most pharmacists without a prescription.

They might also recommend prescription antiviral tablets, such as acyclovir or valacyclovir.

These antiviral drugs are safe for pregnant women and very effective for treating oral and genital herpes.

It’s very common to have cold sores during pregnancy, and it’s generally nothing to worry about.

But it’s always best to check with your doctor, especially if you experience cold sores for the first time during pregnancy.

If you know your baby has been in contact with someone with a cold sore and they develop any of these symptoms, take them to the hospital.

The condition needs to be treated with IV antivirals as soon as possible.

And if you need support along the way, know that your Peanut community is here for you!


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